Communication networks have been designed for campus, corporate, and metropolitan environments. These networks are realized in various topologies, for example, ring, star, and bus. Generally, the network regardless of topology consists of a plurality of nodes physically interconnected by wire, coaxial cable, or optical fiber to form the network. Since interconnections of nodes to the network are physical or "hard-wired," such networks lack the robustness of design sufficient to allow communication with nodes not physically interconnected on the network. That is, only those nodes physically connected in the network are allowed to communicate among themselves.
Each node in the network represents a network user which has the capability for running a variety of applications and a variety of terminal or communications devices. The applications and devices within a particular node are commonly referred to as user entities. In a multimedia communication environment, user entities may include graphics display devices, text input and text display devices, video devices, facsimile devices, communications handling and administration devices, and the like. When the communication protocols of the network require nodes to communicate via packets, communication for graphics for video types of user entities involve significantly more data and, therefore, more packets than text or communications handling types of user entities. As a result, it is possible and highly probable that the packet traffic destined for one type of user entity at a particular node may congest and overflow the provisioned buffering facilities at that node. In turn, this causes other packet traffic destined for the remaining user entities at the particular node to be ignored or discarded thereby adding overhead retransmission packet traffic to the network.
Existing nodes for such networks offer the capability of setting a single priority threshold on all packet transmissions destined for the node regardless of the particular user entity which will receive the packet. The priority threshold allows the node to ignore all packets whose priority fails to meet or exceed the specified priority threshold for that node. While such an approach permits "screening" of packets and thereby offers a mechanism for congestion reduction at the node, it unfairly locks all user entities into receiving only those packets having a sufficiently high priority to meet or exceed the threshold. There is no ability to permit selected user entities to receive packets whose priority is less than the threshold set in the node.